1998 ice storm impact on sugar bushes of eastern Ontario

Abstract

In 1998, thirty-four managed sugar bush blocks with 7% to 72% ice-induced crown damage were established in eastern Ontario. All received dolomitic lime (Ca, Mg) and P and K treatments in June 1999. Initial crown damage, fall root starch and sugar levels, sap production and sweetness, sap amino acid concentration, and tap hole closure rate were measured. Syrup production was calculated. Trees with >50% (severe) crown damage had reduced root starch content in 1998 and 2000, but not in 1999. In 2000, root total sugars were lower in trees with >50% crown damage. Sap produced per tap, and sap sweetness were reduced by damage, but not consistently in all years. Sap per tap increased with total crown branches in all three years, but sap sweetness and syrup production only in 1999. Syrup production per tap was consistently reduced in damaged trees in all three years, usually in trees with > 50% damage. The lime and P and K treatments did not significantly affect any of the variables measured. Results suggest that severe ice storm damage to crowns resulted in reduced fall root starch levels and less sap production, and/or sap sweetness, and therefore lowered the syrup producing capacity of sugar maple. Key words: Acer saccharum, ice storm, sap and syrup production, root starch, crown damage